They're being helped by a $210,000 federal grant that pays for genetic testing.
Investigators on the Montgomery County Cold Case Task Force are looking for DNA on evidence that doesn't include blood.
That can be sweat stained clothing, chewed gum and sealed envelopes.
Ken Betz of the county coroner's office says he believes cases will be solved.
He says new DNA evidence can help investigators
re-interview witnesses or look at other evidence in a new light.
So far the squad has made one arrest in a 1985 killing.
But a Montgomery County grand jury asked for more information and did not indict the suspect.
The Associated Press